** SQL across the Network Question, please help **

If you refer to a table in SQL by its "full path", such as "dbase_name@machine_name:table_name" and you are already on machine machine_name when you execute the SQL (in my case in a 4gl program), is there any overhead in doing this, or does the engine / 4gl resolve the fact that you are already on that box and therefore it will not make any difference. The reason I ask is it seems to me a very safe way to refer to a table given that different machines may have the same database names and table names and you may be runnng an SQL which updates data on different machines. I hope this makes sense? Potential Responders, please also reply to me by email, Thank you !